The present invention relates to the manual actuation of spring-loaded fold-down door restrainers in freight loading systems, particularly in the door latch area for freight and cargo space in an aircraft.
Generally speaking, containers and freight pallets must be securely held in the respective vehicle; or at least steps must be taken to prevent these objects from moving while the vehicle moves. In view of the rather high acceleration and deceleration forces that occur in an aircraft, the problem is, indeed, a significant one in this particular environment. On the other hand, speed is of the essence in handling and moving of air cargo; this includes, in particular, loading and unloading times. Thus, one needs cargo restraining devices that will hold, e.g., a container or a pallet firmly and securely but is easily retractable.
A retractable restraint is particularly required for restraining cargo near the door of the aircraft through which the cargo passes during loading and unloading. U.S. Pat. No. 3,709,450 discloses a system for on-board cargo and load handling in aircraft which includes manually operable, retractable cargo restrainers near doors. The device used here includes a lever in order to retract such a restrainer to a position below the floor and conveyor plane of load-moving and load-positioning. This means that pallets and containers, and so forth, can be rolled over the retracted restrainers during cargo-loading and unloading. The cargo pieces force the restrainer against the force of a spring into a position underneath the conveyor plane so that the cargo can pass through the door; but, thereafter, these restrainers are returned to the protracted position.